Foot warming devices, in and of themselves, are not new. For example, U.S. Pat. Nos. 595,519 and 13,859 disclose box structure having a removable lid so that access can be gained to the container cavity in which a fuel module is placed. U.S. Pat. No. 3,585,736 discloses a shoe having an integral sole in which a chamber is defined to house a fuel module. U.S. Pat. No. 4,094,080 discloses that fabric sections can be stitched together so as to form plural pockets overlying the toe, instep and vamp portions of a boot or shoe such that flameless heaters can be disposed within each pocket to provide warming functions.